Understanding how oligosaccharide structure controls these cellular recognition events has major implications for the treatment of many infectious diseases. Furthermore, understanding oligosaccharides structures and bio-synthesis are critical elements for discovering new chemotherapies. Due to the growing problem of bacterial resistance, there is a great need for new antibacterial/antifungal compounds. The project proposed herein is a tandem synthetic/biological investigation of the papulacandins, a class of potent mono-, di-, and trisaccharide antifungal antibiotics. Our study revolves around a unique de novo asymmetric synthetic approach to the papulacandin ring system, which should allow for easy access to these di and trisaccharides. In addition, this approach will allow simple access to unnatural analogs of this class of natural products and allow for easy screening for activity. Access to the papulacandin ring system and analogs will enable us to probe the mechanism of action to this antifungal agent and ultimately allow for the discovery of new more potent and stable antifungal agents. Additionally, these biological studies should also lead to new antibacterial, anticancer and antiviral compounds.